You probably know high blood pressure is dangerous for your heart. But did you know it’s also dangerous for your brain? And it’s not just about strokes, either. High blood pressure is also one of the most significant risk factors for dementia [1].
And here’s a troubling fact. What we thought was a healthy blood pressure level may actually be doing harm, needlessly raising our risks of cognitive decline.
In this article, we’ll explore a brand-new study giving us fresh evidence that we need to lower our blood pressure more than we thought. We’ll look at what our new target blood pressure should be, according to the research.
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Table of Contents
Section 1: High BP and Dementia
But first, let’s unpack something I just said that might sound surprising — that high blood pressure is a key risk factor for dementia. What evidence do we have for this connection?
One cohort study in Hawaii included almost 4,000 men. Scientists checked their blood pressure in middle age and then looked for signs of dementia 20 years later. They found a strong association between midlife blood pressure and dementia in old age. Those with high blood pressure, when they were younger, had nearly 5 times the risk of dementia compared to those with normal blood pressure [2].
Researchers in Finland found similar results. Once again, people had their blood pressure checked in middle age and were assessed for dementia when older. Those with elevated blood pressure had 2.3 times the risk of dementia later in life [3].
There’s even evidence that elevated blood pressure in early adulthood leads to signs of cognitive decline by midlife [4].
So the clinical evidence points to a definite link between blood pressure and dementia. And we’re going to look at the new study soon which gives us important new details. But why is there a link? What’s behind the connection?
The brain requires a large volume of blood to supply energy and oxygen. It’s filled with blood vessels, many of which are tiny and sensitive. Elevated blood pressure puts stress on the whole system, causing several problems at once.
It damages blood vessels, increases inflammation, and generates oxidative stress, which accelerates neuron aging. Plus, as the body responds to this damage over time, our vessels get stiffer and can form plaques. This makes the problem even worse. As we age, our brains gradually lose the ability to adjust to higher pressure and repair the damage.
This accumulated damage to the brain is a root cause of dementia.
And that’s why studies often look at blood pressure in midlife. Brain damage from high blood pressure doesn’t happen immediately. The body has mechanisms to temporarily guard the brain against the effects of high pressure. But over time, significant damage can accumulate.
So that’s why we can’t wait until we are diagnosed with dementia to do something about high blood pressure. Prevention is far better than treatment. The time to address it is now. The younger, the better.
Section 2: New Targets
And that leads to a crucial question. When it comes to blood pressure, how high is high? What level is safe?
Two groundbreaking studies have completely changed our answer to this question. These studies show that we as doctors got it wrong. For decades we knew that high blood pressure was dangerous, but we didn't realize just how dangerous—even at levels that seemed okay.
For a long time, doctors believed that having a systolic blood pressure — that’s the top number on your reading — up to 140 was perfectly fine. You may have even heard your doctor say that as long as your blood pressure is under 140 over 90, you’re in the clear. We used to think, “Okay, 120/80 is ideal, but 140? That’s still okay, right?”
We now know that having a systolic blood pressure near 140 is actually risky. It’s not just ‘okay’—it’s putting our lives in danger.
The reason doctors thought 140 was fine is that blood pressure tends to go up as we get older, so they figured a little higher was normal. But new research shows even that little extra pressure can cause big problems.
The first wake-up call came from the SPRINT study, which stands for the Systolic Blood Pressure Intervention Trial. This study was massive—over 9,000 participants—so the findings are hard to ignore.
The goal was to see if lowering blood pressure to below 120 would protect against heart attacks, strokes, and other problems better than using the older target of 140.
The people in this study were at high risk for heart disease, but they didn’t have diabetes or a history of stroke. They were split into two groups: One aimed for a blood pressure below 140, and the other aimed for less than 120.
Now, here’s where it gets really interesting—the results were so clear that they had to stop the study early!
The study was supposed to last 4-6 years, but after just 3.3 years, it was obvious that lowering blood pressure to below 120 made a huge difference. There was a 27% lower risk of having a heart attack, stroke, or dying from these causes each year [5].
And when it came to death rates alone, there was a 25% lower risk of dying in the group that aimed for 120 [6].
Let that sink in for a moment—a 25% reduction in the risk of death just by lowering blood pressure more aggressively. This isn’t a small improvement; it’s a game-changer.
But the story doesn’t stop there. Recently, another study in China tested these findings on an even larger and more diverse group—over 11,000 people. And it included those with diabetes and those who had already had a stroke.
Think of this study as a sequel to the SPRINT study but with an even bigger cast. And guess what? The results were just as powerful.
Lowering systolic blood pressure to less than 120 reduced the risk of heart attacks, strokes, and death from cardiovascular causes by 12% [7].
Plus, it cut the overall risk of death from any cause by 21% over three and a half years [8].
The takeaway is clear: the old “normal” of 140 is no longer good enough. Most of us should aim for a systolic blood pressure of less than 120 to really protect our health.
Section 3: The New Study
But these studies focused on heart attacks, strokes, and all-cause mortality. What about dementia risk? Do we know anything about the safe blood pressure level for that? Thanks to the new study, we now do.
This study is actually a follow-up analysis of the group used in the SPRINT study we looked at above. In this new study, researchers looked at the risks of developing dementia. Would they find the same pattern they did for heart attacks and strokes? The pattern was the same. Those who were given the lower blood pressure target had a 14% lower chance of developing dementia during the follow-up period [9].
This is a significant finding, and another study adds one more piece of evidence that points in the same direction. It found that middle-aged women with blood pressure between 120 and 139 had increased evidence of cognitive decline a decade later. It wasn’t yet dementia, but it’s an indication their brains were suffering damage. The researchers suggest reducing blood pressure below 120 to reduce our risks of cognitive decline [10].
All of this gives us strong evidence that getting our blood pressure below 120 isn’t just the right target for our hearts. It’s the right target for our brains, too.
Section 4: How to Lower
So what can we do to lower our blood pressure to a healthy level? Here are some of the most important actions we can take.
One of the simplest is to reduce our salt intake. The American Heart Association recommends that we have no more than about 1/2 teaspoon (or 1,500 milligrams) per day.
Compare that with the 3,500 milligrams the average American eats daily.
How significant is sodium intake? One study that looked at 85 different trials found a clear pattern: as sodium intake goes up, so does blood pressure [11].
The reason is simple. Sodium causes your body to retain more water, increasing the volume of your blood. If there is a greater amount of fluid in your blood vessels, it makes sense that the pressure would increase. It’s similar to the way a balloon stretches tighter and tighter as you blow more air into it.
A salt substitute is a good option for some people.
The second thing we can do to control blood pressure is to shift the way we eat. Researchers have developed guidelines called the DASH diet, which stands for “Dietary Approach to Stop Hypertension.” As you can tell from the name, it’s specifically designed to lower blood pressure.
One analysis looked at several types of interventions to lower blood pressure. It concluded the DASH diet might be the most effective way to lower blood pressure without using medications [12].
The DASH diet is simple. Choose vegetables, fruits, low-fat dairy, whole grains, chicken, fish, and nuts, while minimizing consumption of sweets, sugary drinks, and red meat. It’s high fiber, high lean protein, and packed with nutrients.
As an added bonus, when we follow the DASH diet, we’re also more likely to increase our intake of potassium through potassium-rich foods like spinach, bananas, peas, and beans.
Why is this a bonus? Because potassium helps lower blood pressure. It balances out sodium levels while also encouraging the walls of our blood vessels to relax. Its powerful effect is the reason I include it in MicroVitamin. Just because I take a supplement, though, doesn’t mean you have to also.
The third key strategy to lower blood pressure is adding exercise. I know how hard it can seem to get started, especially if you have been relatively inactive.
The good news is that even small changes can make a positive impact. I encourage my patients to start where they are and look for ways to add movement into their schedules. I recommend they try exercise snacks. They’re short bursts of physical activity that you sprinkle throughout your day—like mini-workouts instead of one long training session. Instead of carving out a 30-minute chunk of time to hit the gym, you might do a few sets of wall squats between meetings, for example.
I do an exercise snack during my 15-minute paperwork breaks at the clinic.
Finally, for overweight individuals, weight loss can be a powerful contributor to getting elevated blood pressure under control. One study showed that the greater the weight loss, the greater the reduction in blood pressure [13].
Fortunately, though losing weight can be challenging, making the changes we’ve talked about so far will make this much easier.
But if our weight is above target, despite optimizing our lifestyle factors, we can consider medications such as Ozempic to help on our weight loss journey. Taking medication isn’t a failure—it’s another tool to help reach our health goals.
And finally, if our lifestyle factors are dialed in, weight is perfect, but we still have a blood pressure above 120, then I have a discussion with my patients about the pros and cons of blood pressure medications. I emphasize that medication should be an addition to, not a replacement for, all the other steps.
Reference List
1. https://www.ahajournals.org/doi/10.1161/hyp.0000000000000053
2. https://www.sciencedirect.com/science/article/abs/pii/S0197458000000968?via%3Dihub
3. https://www.bmj.com/content/322/7300/1447
4. https://pubmed.ncbi.nlm.nih.gov/24687777/
5. https://www.nejm.org/doi/10.1056/NEJMoa1901281
6. https://www.nejm.org/doi/10.1056/NEJMoa1901281
7. https://pubmed.ncbi.nlm.nih.gov/38945140/
8. https://pubmed.ncbi.nlm.nih.gov/38945140/
9. https://www.neurology.org/doi/abs/10.1212/WNL.0000000000213334
10. https://pubmed.ncbi.nlm.nih.gov/25814553/
11. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8055199/
12. https://pmc.ncbi.nlm.nih.gov/articles/PMC7792371/
13. https://www.uptodate.com/contents/image?imageKey=NEPH%2F60178&topicKey=PC%2F3852&source=see_link
